Audacity

Audacity is an easy-to-use, multi-track audio editor and recorder for Windows, macOS, GNU/Linux and other operating systems. Audacity is open source software licensed under GPL, version 2 or later.

Recording from any real, or virtual audio device that is available to the host system.
Export / Import a wide range of audio formats, extendible with FFmpeg.
High quality using 32-bit float audio processing.
Plug-ins Support for multiple audio plug-in formats, including VST, LV2, AU.
Macros for chaining commands and batch processing.
Scripting in Python, Perl, or any language that supports named pipes.
Nyquist Very powerful built-in scripting language that may also be used to create plug-ins.
Editing multi-track editing with sample accuracy and arbitrary sample rates.
Accessibility for VI users.
Analysis and visualization tools to analyze audio, or other signal data.